168 WEBER ON THE CONNEXION OF DIAMAGNETISM 



for, and hence molecular currents alone are available here. 

 Developing with regard to these molecular currents, in accord- 

 ance with the laws of magnetic induction, the dependence of 

 the moment of ideal distribution upon the magnitude of the 

 magnetizing force in operation, we find, that if in the line of 

 magnetization the direction in which the north pole of a mag- 

 netic needle is driven be called the positive, and the centres of 

 gravity of the north and south fluids, according to the ideal 

 distribution dependent on the magnetizing force, be determined, 

 the former of these in comparison with the latter is situated in 

 the negative direction, which is exactly the reverse of what takes 

 place in the other three cases. This enables us to render an 

 account of the inner cause of diamagnetism. 



Internal Cause of Diamagnetism. 



This remarkable result may be applied to the founding of a 

 theory of diamagnetic phaenomena, which shall assign an origin 

 to the forces which produce them, a subject hitherto unexplained. 

 For such a theory it is not sufficient that the diamagnetic state 

 of a body may be conveniently represented by an ideal distribu- 

 tion of the magnetic fluids over its surface, but it is essential 

 that it shall render an account of the forces which produce the 

 diamagnetic state, and also of the laws according to which these 

 forces act. 



From the above statement and consideration of the different 

 possible ways in which a condition representable by an ideal 

 distribution might be developed in a body, one case alone was 

 found from which a law coinciding with the fundamental phae- 

 nomena of diamagnetism resulted. It follows from this, that an 

 explanation of the development of the diamagnetic state can 

 only be given when this case is regarded as actually existing ; 

 according to it the increase of the diamagnetism of a body is 

 proportional to the inducing force acting upon the electric fluids, 

 causing them to move without resistance in definite circular 

 paths around the molecules, and accelerating the velocity of their 

 movement in these paths. The diamagnetism of bismuth, for 

 example, is explained by the assumption that the molecules of 

 bismuth contain within them definite paths or canals, in which 

 the electric fluids move without resistance, while in all other 



